[LOG4J2-3281] Log4j 1.2 bridge PropertiesConfiguration.buildAppender not adding filters to custom appender

• Type: Bug
• Status: Resolved
• Priority: Blocker
• Resolution: Fixed
• Affects Version/s: 2.17.1, 2.17.0
• Fix Version/s: 2.17.2
• Component/s: Appenders, Configurators
• External issue ID: LOG4J2-3247
• Assignee: Unassigned
• Reporter: Fábio Constantino
• Created: 23/Dec/21 13:38
• Updated: 04/Jan/22 22:15
• Resolved: 31/Dec/21 15:00

Description

When building an appender, the parseAppenderFilters method correctly finds my custom filter configuration in the properties file, builds it and returns it, but the caller (buildAppender method) does nothing with it resulting in the appender not having any filters added to it.

 

This is related to the linked issue - LOG4J2-3247 - where the scenario is the same (properties file config):

log4j1.compatibility=true

log4j.appender.LOG_REQUEST_START_DB=my.appender.class
log4j.appender.LOG_REQUEST_START_DB.filter.ID=my.filter.class 

the Filter class I'm working with is the following:

import org.apache.log4j.spi.Filter;
import org.apache.log4j.spi.LoggingEvent;

public class MonitorFilter extends Filter {
    @Override
    public int decide(LoggingEvent event) {
        String requestId = (String)event.getMDC("requestId");
        if (StringHelper.isNullOrEmpty(requestId))
            return DENY;        
        
        if (!MonitorScriptManager.getInstance().getMonitorScript().filter(event))
            return DENY;
        
        return ACCEPT;
    }
} 

I am using the following log4j dependencies:

        <dependency>
            <groupId>org.apache.logging.log4j</groupId>
            <artifactId>log4j-core</artifactId>
            <version>2.17.0</version>
        </dependency>
        <dependency>
            <groupId>org.apache.logging.log4j</groupId>
            <artifactId>log4j-api</artifactId>
            <version>2.17.0</version>
        </dependency>
        <dependency>
            <groupId>org.apache.logging.log4j</groupId>
            <artifactId>log4j-1.2-api</artifactId>
            <version>2.17.0</version>
        </dependency>